Electro Magnetic Interference
I think the possibility of EMI being involved in this (and/or other incidents) is being too easily dismissed by some. (And NO, I am not saying that I'm sure this is the case here!)
Though the math is no doubt correct (I'm definitely not qualified to question it) on the posts relating to propagation, I think there is some confusion between carrier frequencies and RF energy itself. For instance ELF (extra low frequency) is tricky stuff and as I'm sure some ppruners are aware it can be used it as a weapon. The principal is the same as an EMP burst, as ELF can generate high intensity EM field and unfortunately any "electronics" can be susceptible -- especially gyro-based computer components. Previous comments about higher frequency RF are in principal correct, but there is also reason to discount the notion that whatever transmitter(s) may be involved, they would be directed at the surface, as opposed to the ionosphere.
Lots of sources of interesting info out there, but for many, this might be an interesting start: High Frequency Active Auroral Research Program - Wikipedia, the free encyclopedia
Grizz